At first it may seem strange that such a fantastic and obvious frog (up to almost 10 cm body length) could escape discovery until now, less than 100 km from an urban centre with over 9 million people. But these frogs are called Flying Frogs for a reason, and it’s their arboreal nature that likely kept them out of view from biologists for so long.

The term “Flying Frog” is used to describe many frogs in the genus Rhacophorus, but Helen’s Flying Frog belongs to the group of frogs that have the greatest ability glide. Armed with large hands and feet that are fully webbed, and even having flaps of webbing on the outside of their arms, Helen’s Tree Frog is able glide gracefully down from trees to breed in forest pools, and probably even glide from tree to tree. Because they likely spend most of the time in the forest canopy, they’ve remained largely out of sight.

To date, Helen’s Tree Frog is still only known from two patches of lowland forest surrounded by a sea of agricultural land in southern Vietnam. Lowland forests are among the most threatened habitats in the world, largely because they are so accessible (no mountains for people to scale in order to get there!).

While Helen’s Tree Frog has only just been discovered by biologists, unfortunately this species, like many others, is under great threat from ongoing habitat loss and degradation.

Our discovery was a collaboration between biologists at the Australian Museum (Sydney, Australia), the University of Science–Ho Chi Minh City (Ho Chi Minh City, Vietnam), and Zoologisches Forschungsmuseum Alexander Koenig (Bonn, Germany); and supported by funding from Ocean Park Conservation Foundation Hong Kong, ADM Capital Foundation, The John D. and Catherine T. MacArthur Foundation, the University of Science Ho Chi Minh City, the Ministry of Education and Training of Vietnam, and the German Academic Exchange Service (DAAD).